Heretic: small visual improvements (#1117)

* Weapons drawn 1 pixel too high when player is idle

This approach is same to Crispy Doom, and it's working as it should.

* Fix 1px gap between translucent PSPrite and STbar

Same approach as in R_DrawFuzzColumn.

* Allow translucent weapons to be affected by invul colormap

* Better approach for fixing gap between translucent weapon and status bar

Co-Authored-By: ceski <56656010+ceski-1@users.noreply.github.com>

* Remove redundant changes

* Interpolate scrolling flats

Adopted from commit:
0ab96c0#diff-385affd7076e37a2aa4b0e489fff3bbe8a4ee5fff3cc62f41655c4ee9d92457e

Co-Authored-By: Michael Day <43701387+mikeday0@users.noreply.github.com>

---------

Co-authored-by: ceski <56656010+ceski-1@users.noreply.github.com>
Co-authored-by: Michael Day <43701387+mikeday0@users.noreply.github.com>

src/heretic/r_draw.c

@@ -178,10 +178,13 @@ void R_DrawTLColumn(void)
     fixed_t frac, fracstep;
     int heightmask = dc_texheight - 1; // [crispy]
 
+    // [crispy] Show transparent lines at top and bottom of screen.
+    /*
     if (!dc_yl)
         dc_yl = 1;
     if (dc_yh == viewheight - 1)
         dc_yh = viewheight - 2;
+    */
 
     count = dc_yh - dc_yl;
     if (count < 0)

src/heretic/r_plane.c

@@ -74,6 +74,8 @@ fixed_t cacheddistance[MAXHEIGHT];
 fixed_t cachedxstep[MAXHEIGHT];
 fixed_t cachedystep[MAXHEIGHT];
 
+static fixed_t xsmoothscrolloffset; // [crispy]
+static fixed_t ysmoothscrolloffset; // [crispy]
 
 /*
 ================
@@ -169,6 +171,10 @@ void R_MapPlane(int y, int x1, int x2)
     ds_xfrac = viewx + FixedMul(viewcos, distance) + dx * ds_xstep;
     ds_yfrac = -viewy - FixedMul(viewsin, distance) + dx * ds_ystep;
 
+     // [crispy] add smooth scroll offsets
+    ds_xfrac += xsmoothscrolloffset;
+    ds_yfrac += ysmoothscrolloffset;
+
     if (fixedcolormap)
         ds_colormap[0] = ds_colormap[1] = fixedcolormap;
     else
@@ -409,6 +415,8 @@ void R_MakeSpans(int x, unsigned int t1, unsigned int b1, unsigned int t2, unsig
 ================
 */
 
+extern fixed_t fractionaltic; // [crispy]
+
 #define SKYTEXTUREMIDSHIFTED 200 // [crispy]
 
 void R_DrawPlanes(void)
@@ -425,6 +433,7 @@ void R_DrawPlanes(void)
     int count;
     fixed_t frac, fracstep;
     int heightmask; // [crispy]
+    static int interpfactor; // [crispy]
 
 #ifdef RANGECHECK
     if (ds_p - drawsegs > numdrawsegs)
@@ -552,20 +561,44 @@ void R_DrawPlanes(void)
 
         tempSource = W_CacheLumpNum(lumpnum, PU_STATIC);
 
+        // [crispy] Use old value of interpfactor if uncapped and paused. This
+        // ensures that scrolling stops smoothly when pausing.
+        if (crispy->uncapped && leveltime > oldleveltime)
+        {
+            // [crispy] Scrolling normally advances every *other* gametic, so
+            // interpolation needs to span two tics
+            if (leveltime & 1)
+            {
+                interpfactor = (FRACUNIT + fractionaltic) >> 1;
+            }
+            else
+            {
+                interpfactor = fractionaltic >> 1;
+            }
+        }
+        else if (!crispy->uncapped)
+        {
+            interpfactor = 0;
+        }
+
         switch (pl->special)
         {
             case 25:
             case 26:
             case 27:
             case 28:
             case 29:           // Scroll_North
+                xsmoothscrolloffset = 0;
+                ysmoothscrolloffset = 0;
                 ds_source = tempSource;
                 break;
             case 20:
             case 21:
             case 22:
             case 23:
             case 24:           // Scroll_East
+                xsmoothscrolloffset = -(interpfactor << (pl->special - 20));
+                ysmoothscrolloffset = 0;
                 ds_source = tempSource + ((63 - ((leveltime >> 1) & 63)) <<
                                           (pl->special - 20) & 63);
                 //ds_source = tempSource+((leveltime>>1)&63);
@@ -575,20 +608,28 @@ void R_DrawPlanes(void)
             case 32:
             case 33:
             case 34:           // Scroll_South
+                xsmoothscrolloffset = 0;
+                ysmoothscrolloffset = 0;
                 ds_source = tempSource;
                 break;
             case 35:
             case 36:
             case 37:
             case 38:
             case 39:           // Scroll_West
+                xsmoothscrolloffset = 0;
+                ysmoothscrolloffset = 0;
                 ds_source = tempSource;
                 break;
             case 4:            // Scroll_EastLavaDamage
+                xsmoothscrolloffset = -(interpfactor << 3);
+                ysmoothscrolloffset = 0;
                 ds_source =
                     tempSource + (((63 - ((leveltime >> 1) & 63)) << 3) & 63);
                 break;
             default:
+                xsmoothscrolloffset = 0;
+                ysmoothscrolloffset = 0;
                 ds_source = tempSource;
         }
         }

src/heretic/r_things.c

@@ -797,8 +797,9 @@ void R_DrawPSprite(pspdef_t * psp)
     vis->mobjflags = 0;
     vis->psprite = true;
     vis->footclip = 0;
+    // [crispy] weapons drawn 1 pixel too high when player is idle
     vis->texturemid =
-        (BASEYCENTER << FRACBITS) /* + FRACUNIT / 2 */ - (psp->sy2 -
+        (BASEYCENTER << FRACBITS) + FRACUNIT / 4 - (psp->sy2 -
                                                     spritetopoffset[lump]);
     if (viewheight == SCREENHEIGHT)
     {
@@ -825,7 +826,9 @@ void R_DrawPSprite(pspdef_t * psp)
         viewplayer->powers[pw_invisibility] & 8)
     {
         // Invisibility
-        vis->colormap[0] = vis->colormap[1] = spritelights[MAXLIGHTSCALE - 1];
+        // [crispy] allow translucent weapons to be affected by invulnerability colormap
+        vis->colormap[0] = vis->colormap[1] = fixedcolormap ? fixedcolormap :
+                                              spritelights[MAXLIGHTSCALE - 1];
         vis->mobjflags |= MF_SHADOW;
 #ifdef CRISPY_TRUECOLOR
         vis->blendfunc = I_BlendOverTinttab;